In the operation of many chemical systems it is necessary to utilize glass columns, vessels, conduits and piping, due to the corrosion resistance properties of glass, and particularly borosilicate glasses, such as Corning Code 7740. The glass components within the chemical system may include such items as columns, reducers, flasks, T's, elbows, and other processing components, all of which are provided with integral end flange portions utilized for connecting the various components together in an overall chemical processing system.
Under working conditions the coupled tubular members forming the columns and flow conduits for the chemical system are subjected to various forces, due to operating temperatures and pressures of the system, which tend to impart bending or bulging deformations resulting in the inducement of undesirable stresses and strains in the system. Depending upon the particular usage or operating parameters within the system, the bending moments or deformations imparted to the tubular members such as columns or pipes forming such system may be outwardly, forming a convex shape when internal pressures are generated within the system, or on the contrary may be bowed inwardly or of a concave shape when the system is operated under subatmospheric or reduced pressures relative to the pressures to which the outer walls of the system are subjected. In view of the fact that glass does not exhibit the property of plastic flow, fracture occurs under tension before there is any permanent deformation of the glass body, and accordingly for safety purposes in order to avoid the risk of rupture and failure, there are definite limits to which the tubular glass members may be subjected.
Accordingly, the present invention has overcome the problems of severe deformation and induced stresses resulting during the operation of columnar processing systems, by substantially increasing or broadening the operating limits which may be employed by the system. That is, the strength of the various elements or tubular members forming the processing system is substantially increased under operating conditions, by preinducing deformation and stresses within the tubular columns counter to that experienced during operating conditions, so that the net algebraic result of the opposing forces will be minimized to provide a substantially balanced system. Accordingly, the coupling concept of the present invention has particular applicability with respect to the utilization of flanged glass tubular members of relatively large diameters of up to about 4 or 5 feet.